Verticle thermoforming apparatus

Abstract

An apparatus for thermoforming plastic sheet material which has a frame and complementary mold halves mounted on the frame for movement toward and away from one another. The apparatus has an indexing means which moves along a vertical path to pull the plastic material through the mold and a clamping means disposed between the mold halves which operates with the mold to clamp the plastic sheet around the edges of the forming tool of one mold half. The indexing means and clamping means operate to reduce sag of the plastic material and improve uniformity of the finished article. Operation of the apparatus is enhanced by the use of air pressure, vacuum and cooling during molding and release.

We claim: 
     
       1. An apparatus of thermoforming plastic sheet material into desired forms in a manner so as to minimize material waste and improve product quality, comprising: a. a forming station including complementary first mold means and second mold means moveable toward and away from each other along a horizontal axis, one of said mold means having at least one forming tool therein;   b. indexer means disposed above and adjacent to said mold means for moving said plastic material into said forming station without the use of a chain rail or clamping rail running along side material vertically between said mold means such that the length of said plastic material runs on an upward path of travel from the bottom toward the top of said apparatus to eliminate sagging of said material and the need for said chain rails or said clamping rail during a molding operation; said indexer means being moveable along a vertical path in a reciprocal manner relative to said mold means;   c. means for moving said mold means adjacent one another in said molding operation with said plastic material disposed vertically there between, said mold means cooperating to form a molded article;   d. means disposed between said first mold means and said second mold means to clamp said plastic sheet material around said forming tool in one of said mold means during said molding operation to thereby isolate and individually secure around all of its borders each area of sad plastic forming tool and provide more uniform drawing of said plastic material.   
     
     
       2. The thermoforming apparatus of claim 1, including assist means for facilitating said molding operation and release from said mold means of said thermoformed article. 
     
     
       3. The apparatus of claim 2 wherein said assist means includes positive air pressure supply means directed to one of said mold means and negative air pressure supply means directed to the other of said mold means during molding, said assist means being reversibly directed to the opposite one of said mold means after molding. 
     
     
       4. The apparatus of claim 3 further including plug assist means mounted on one of said mold means. 
     
     
       5. The thermoforming apparatus of claim 1, including a frame, a plurality of generally horizontal, parallel rods mounted on said frame, first mold means and second mold means mounted on said rods for sliding movement therealong, and means for moving said first mold means and said second mold means toward and away from one another along said rods. 
     
     
       6. The apparatus of claim 5 wherein said means for moving said mold means includes hydraulic means. 
     
     
       7. The thermoforming apparatus of claim 5, wherein said means to clamp said plastic material against one of said mold means is a clamping tool which is mounted on said generally parallel rods mounted on said frame, said clamping tool having at least one opening formed therein generally corresponding in outline to said forming tool, said clamping tool when positioned adjacent said forming tool with said plastic sheet therebetween acting to prevent said plastic sheet from moving relative to said forming tool during molding to provide uniform drawing of said plastic sheet. 
     
     
       8. The apparatus of claim 1 wherein said means to clamp said plastic material against said mold means includes a resilient sealing means disposed on an opposite side of said plastic sheet from said means to clamp to provide better sealing between said mold means, said plastic sheet and said means to clamp. 
     
     
       9. The thermoforming apparatus of claim 1 wherein one of said mold means has multiple forming tools formed therein and said means to clamp has openings formed therein corresponding in shape and location to each of said forming tools. 
     
     
       10. The thermoforming apparatus of claim 1 including means to cool said mold means during said molding operation. 
     
     
       11. The thermoforming apparatus of claim 10 wherein said means to cool said molding apparatus includes a tooling plate mounted adjacent said mold means, said tooling plate having circulation passageways formed therein to receive and circulate a cooling fluid therethrough to permit the transfer of heat from said mold means to said cooling fluid. 
     
     
       12. The thermoforming apparatus of claim 1 including heating means disposed adjacent the upward path of travel of said plastic sheet means and operating to heat selected portions of said plastic sheet prior to molding to facilitate thermoforming of said sheet. 
     
     
       13. The thermoforming apparatus of claim 1 additionally including cutting means designed to cut each thermoformed part from the sheet of material fed to said cutting means. 
     
     
       14. The thermoforming apparatus of claim 1 wherein said indexer means includes a jaw means having a first clamping portion in a complimentary second clamping portion, said clamping portions being movable toward and away from one another along a horizontal axis, said first and second clamping portions being operable to engage opposite faces of said plastic sheet material to hold said plastic sheet in a position such that its length runs vertically from the bottom to the top of said apparatus. 
     
     
       15. The thermoforming apparatus of claim 14 wherein each of said first and second clamping portions include elongated edge means which are operable to grip said plastic material substantially across its width, said edge means being movable together in a vertical manner when gripping said plastic material to raise said plastic material. 
     
     
       16. In an apparatus for thermoforming plastic sheet material of high orientation and including frame, complimentary mold means mounted on said frame for movement relative said frame, the improvement comprising means to move said plastic material on an upward path of travel from the bottom to the top of said apparatus in a vertical manner relative to said mold means such that said plastic material remains essentially vertical at all times during molding, said means to move said plastic material comprising a pair of opposed indexing jaws mounted on said frame above said mold means and movable horizontally toward and away from one another and vertically as a pair toward and away from said mold means.